How to test Optional.orElseThrow() (Java)?

[elysha]

I have a method using a repository using Optional.orElseThrow inside a service.

How to correctly implement the construction

when(restLogRepository.findById(anyLong()).thenReturn(log);

My way is obviously wrong

Service

public RestLogDto readById(Long id) {
    return DtoConverter.convert(
        restLogRepository.findById(id).orElseThrow(() -> new NoSuchElementException("Element not found")),
        modelMapper);
    }

My Test method (wrong)

@Test
public void readById() {
    RestLog log = new RestLog();
    log.setLogId(LOG_ID);

    when(restLogRepository.findById(anyLong()).orElseThrow(any(Supplier.class))).thenReturn(log);
    RestLogDto result = DtoConverter.convert(log, mapper);

    assertEquals(result, logReader.readById(LOG_ID));
}

[Oba22]

DtoConverter entity = spy(new DtoConverter());
entity.setId(5);
doReturn(Optional.of(entity)).when(restLogRepository).findById(any());

assertEquals(5, logReader.readById(5));